JP5181899B2 - Image reading apparatus and image forming apparatus - Google Patents

Image reading apparatus and image forming apparatus Download PDF

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Publication number
JP5181899B2
JP5181899B2 JP2008192835A JP2008192835A JP5181899B2 JP 5181899 B2 JP5181899 B2 JP 5181899B2 JP 2008192835 A JP2008192835 A JP 2008192835A JP 2008192835 A JP2008192835 A JP 2008192835A JP 5181899 B2 JP5181899 B2 JP 5181899B2
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image
positive power
optical system
reading apparatus
reflecting surface
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JP2010032652A (en
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一成 安部
喜一朗 仁科
昌弘 伊藤
和弘 藤田
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株式会社リコー
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    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/10Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces
    • H04N1/1013Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B17/00Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08Catadioptric systems
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024Details of scanning heads ; Means for illuminating the original
    • H04N1/028Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/03Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array
    • H04N1/0301Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array using a bent optical path between the scanned line and the photodetector array, e.g. a folded optical path
    • H04N1/0303Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array using a bent optical path between the scanned line and the photodetector array, e.g. a folded optical path with the scanned line and the photodetector array lying in non-parallel planes
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/024Details of scanning heads ; Means for illuminating the original
    • H04N1/028Details of scanning heads ; Means for illuminating the original for picture information pick-up
    • H04N1/03Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array
    • H04N1/0301Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array using a bent optical path between the scanned line and the photodetector array, e.g. a folded optical path
    • H04N1/0305Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array using a bent optical path between the scanned line and the photodetector array, e.g. a folded optical path with multiple folds of the optical path
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • G02B13/24Optical objectives specially designed for the purposes specified below for reproducing or copying at short object distances
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/00519Constructional details not otherwise provided for, e.g. housings, covers
    • H04N1/00525Providing a more compact apparatus, e.g. sheet discharge tray in cover
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/10Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces
    • H04N1/1013Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components
    • H04N1/1017Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components the main-scanning components remaining positionally invariant with respect to one another in the sub-scanning direction
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
    • H04N1/191Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
    • H04N1/192Simultaneously or substantially simultaneously scanning picture elements on one main scanning line
    • H04N1/193Simultaneously or substantially simultaneously scanning picture elements on one main scanning line using electrically scanned linear arrays, e.g. linear CCD arrays
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/0077Types of the still picture apparatus
    • H04N2201/0081Image reader
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/0077Types of the still picture apparatus
    • H04N2201/0091Digital copier; digital 'photocopier'
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04NPICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N2201/00Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
    • H04N2201/024Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof deleted
    • H04N2201/02495Constructional details not otherwise provided for, e.g. for ease of assembly, allowing access to the scanning elements, integrated reinforcing members

Description

At least one embodiment of the present invention relates to at least one of an image reading apparatus and an image forming apparatus.

  Until now, various techniques relating to an image reading apparatus, an image reading method, an image forming apparatus, or an image forming method have been developed.

  For example, Japanese Patent Laid-Open No. 2002-107631 (Patent Document 1) has at least a lens group that is rotationally symmetric with respect to the optical axis and one or more free-form surface mirrors, and one-dimensionally captures a document image in an image reading apparatus. A reading optical system for projecting onto an element, which includes an intersection of the reflecting surface of the free-form curved mirror and the optical axis of the lens group, and a plane perpendicular to the one-dimensional arrangement direction of the imaging element, The shape of the reflecting surface of the free-form curved mirror is symmetric, includes a normal line of the free-form curved mirror at the intersection, and is parallel to the one-dimensional arrangement direction of the image sensor. A reading optical system characterized in that the shape of the reflecting surface is asymmetric is disclosed.

  In the reading optical system disclosed in Patent Document 1, the number of lenses included in the lens group is reduced by using a free-form surface mirror in addition to the lens group. In the embodiment disclosed in Patent Document 1, by arranging a free-form surface mirror having a positive power on the image side instead of the object side, a part of aberration that cannot be sufficiently corrected only by the lens is used by the mirror. It has been corrected.

  However, since no intermediate image is formed on the object side, it is difficult to obtain a wide-angle reading optical system, and the object distance of the reading optical system increases. In the embodiment disclosed in Patent Document 1, the distance from the object to the image (the distance between the object images) is 496 mm for the reading optical system having an object height of 150 mm and a reduction magnification of 0.16535, and the entire reading optical system is The length has increased. For this reason, the thickness of the apparatus that accommodates the reading optical system increases, and the overall size of the apparatus increases. In order to reduce the size of the device, even if the optical path between the long object and the lens group is folded by the plane mirror, the number of folding (the number of plane mirrors) increases, and the plane mirror is manufactured. The cost for the installation and position adjustment process increases.

  Furthermore, a free-form surface mirror is disposed on the optical path between the lens group and the image with a short optical path length, that is, on the optical path on the reduction side (image side). For this reason, when assembling an image pickup device arranged on the reduction side of the reading optical system, there is little space for adjusting the position of the image pickup device, which makes it difficult to adjust the position of the image pickup device.

  In Japanese Patent Laid-Open No. 5-3528 (Patent Document 2), an optical head including a one-dimensional reading element and an optical imaging means facing the reading element faces a two-dimensional image original. An image reading apparatus in which a concave mirror is used as the optical imaging means in the image reading apparatus which is disposed and in which the image original and the optical head are relatively moved. Is disclosed.

  In the reading optical system of the image reading apparatus disclosed in Patent Document 2, only a concave mirror that does not generate chromatic aberration is used as an optical imaging means. In the embodiment disclosed in Patent Document 2, since an image is formed by only one concave mirror having power, it is difficult to correct aberrations other than chromatic aberration. Therefore, it is difficult to obtain a wide-angle reading optical system, and the distance between the object images of the reading optical system increases. Accordingly, the thickness of the image reading device will increase, and the size of the image reading device will increase.

  Further, Japanese Patent Application Laid-Open No. 2004-109793 (Patent Document 3) discloses an image reading apparatus having an imaging lens for forming image information of a document and a solid-state imaging device for reading the image information. An image reading apparatus is disclosed in which a mirror having an anamorphic surface is disposed in an optical path between the imaging lens and the solid-state imaging device.

  In the image reading device disclosed in Patent Document 3, in order to correct the difference in the imaging position of the imaging lens in the main scanning direction and the sub-scanning direction, as in the reading optical system disclosed in Patent Document 1, A mirror having an anamorphic surface is arranged in the optical path between the imaging lens and the solid-state imaging device, that is, on the image side, and corrects some aberrations that cannot be sufficiently corrected by the lens. ing.

  However, since no intermediate image is formed on the object side, it is difficult to obtain a wide-angle optical system, and the distance between the object images of the optical system increases. Therefore, the thickness of the image reading apparatus including this optical system increases, and the overall size of the image reading apparatus increases.

Therefore, the present inventor provides a relatively wide-angle optical system having a relatively short distance between object images, and by using such an optical system, the number of times of folding of the optical path of the optical system is relatively small. It has been found that a relatively small image reading apparatus having a small size and a relatively small housing size is provided.
JP 2002-107631 A JP-A-5-3528 JP 2004-109793 A

A first object of the present invention is to provide a smaller image reading apparatus.

A second object of the present invention is to provide an image forming apparatus including a smaller image reading apparatus.

According to a first aspect of the present invention, there is provided an image reading apparatus for reading image information, wherein the image reading apparatus forms an image on an image and an image formed by the image forming optical system. The imaging optical system includes a first optical system that forms the image on an intermediate image and a first optical system that forms the intermediate image on the formed image. The first optical system includes a reflecting surface having a positive power, and the second optical system includes a lens system having an optical axis and a positive power. The imaging optical system further includes at least one reflecting surface that folds an optical path from the image to the reflecting surface having the positive power and has no power, and has the reflecting power having the positive power from the image. The light path to the surface Of the at least one reflecting surface that folds and has no power, the reflecting surface that does not have the power closest to the reflecting surface having the positive power intersects the optical axis of the lens system. An image reading apparatus.

According to a second aspect of the present invention, there is provided an image forming apparatus for forming an image on an image carrier, wherein the image forming apparatus is an image reading apparatus according to the first aspect of the present invention and an image read by the image reading apparatus. An image forming apparatus comprising a device that forms an image on the image carrier using the information of the above.

According to the first aspect of the present invention, it is possible to provide a smaller image reading apparatus.

According to the second aspect of the present invention, it is possible to provide an image forming apparatus including a smaller image reading apparatus.

Next, an embodiment (embodiment) of the present invention will be described.

(Image reading apparatus, image reading method, image forming apparatus, and image forming method)

Embodiments described herein relate generally to an image reading apparatus, an image reading method, an image forming apparatus, and an image forming method.

The first object of the embodiment of the present invention is to provide a smaller image reading apparatus.

A second object of the embodiment of the present invention is to provide an image reading method using a smaller image reading apparatus.

A third object of the embodiment of the present invention is to provide an image forming apparatus including a smaller image reading apparatus.

A fourth object of the embodiment of the present invention is to provide an image forming method using an image forming apparatus including a smaller image reading apparatus.

A first aspect of an embodiment of the present invention includes an imaging optical system that forms an image into an image, and an imaging element that captures at least a part of the image formed by the imaging optical system. In the image reading apparatus for reading information, the imaging optical system includes a first optical system that forms the image on an intermediate image and a second optical system that forms the intermediate image on the formed image. An image reading apparatus including the above.

A second aspect of embodiments of the present invention include an image reading method for reading the information of the image, using an image reading apparatus according to the first aspect of embodiments of the present invention, to read the information of the image An image reading method characterized by the above.

A third aspect of embodiments of the present invention is an image forming apparatus for forming an image on an image bearing member, an image read by the image reading apparatus and the image reading apparatus according to the first aspect of embodiments of the present invention The image forming apparatus includes a device that forms an image on the image carrier using the information of the image.

A fourth aspect of embodiments of the present invention is an image forming method for forming an image on an image bearing member, using the image forming apparatus is a third aspect of embodiments of the present invention, an image to said image bearing member Forming an image.

According to the first aspect of the embodiment of the present invention , it is possible to provide a smaller image reading apparatus.

According to the second aspect of the embodiment of the present invention , it is possible to provide an image reading method using a smaller image reading apparatus.

According to the third aspect of the embodiment of the present invention , it is possible to provide an image forming apparatus including a smaller image reading apparatus.

According to the fourth aspect of the embodiment of the present invention , it is possible to provide an image forming method using an image forming apparatus including a smaller image reading apparatus.

  Next, embodiments of the present invention will be described with reference to the drawings.

  According to a first embodiment of the present invention, image information including an imaging optical system that forms an image into an image and an image sensor that captures at least a part of the image formed by the imaging optical system. In the image reading apparatus for reading, the imaging optical system includes a first optical system that forms the image on an intermediate image and a second optical system that forms the intermediate image on the formed image. This is an image reading apparatus.

  Here, the imaging includes both imaging on an image having no aberration and imaging on an image having aberration. In other words, the image includes both an image without aberration and an image with aberration. In addition, the image and the intermediate image have a conjugate relationship with respect to the first optical system, and the intermediate image and the formed image have a conjugate relationship with respect to the second optical system, and the image and the formed image have been formed. The image has a conjugate relationship with the imaging optical system. The image may preferably be a document image on a document surface provided in the image reading apparatus.

  According to the first embodiment of the present invention, it is possible to provide a smaller image reading apparatus. In particular, according to the first embodiment of the present invention, the imaging optical system includes a first optical system that forms the image into an intermediate image and the intermediate image that is formed into the formed image. Since the second optical system is included, that is, an intermediate image is formed, the first optical system having a large power can be provided. As a result, it is possible to provide a relatively wide-angle imaging optical system having a relatively short distance between object images. Accordingly, the size of the image reading apparatus including the imaging optical system can be reduced accordingly. For example, since the distance between the object images of the imaging optical system is relatively short, the optical path length from the image to the first optical system can be reduced. As a result, the thickness of the image reading apparatus in the vertical direction can be reduced. In addition, even when the optical path from the image to the first optical system is folded by a reflecting surface having no power, the number of folding or the number of reflecting surfaces having no power can be reduced. . As a result, the processing cost of the reflecting surface without power and the manufacturing cost of the reflecting surface without power, such as vapor deposition, and the power when installing the reflecting surface without power in the image reading device This makes it possible to reduce the time and time required for adjusting the position of the reflecting surface.

  The image reading apparatus according to the first embodiment of the present invention is used for an image reading apparatus including a reading optical system, such as a document reading unit of a facsimile and a digital copying machine, and reading optical systems of various image scanners. Is possible.

  In the image reading apparatus according to the first embodiment of the present invention, preferably, the first optical system includes a reflecting surface having a positive power, and the second optical system includes an optical axis and a positive surface. An image reading apparatus including a lens system having the following power.

  Here, the reflecting surface having positive power specifically means a concave reflecting surface. Further, the shape of the reflecting surface having positive power may be either a spherical shape or an aspherical shape. However, in order to correct or reduce the aberration of the imaging optical system, it is preferable that the reflecting surface has an axisymmetric aspherical surface. Shape and aspheric shape such as anamorphic aspheric shape. Further, the number of reflecting surfaces having positive power may be one or plural, but is preferably one in order to reduce the size of the configuration of the imaging optical system.

  A lens system having an optical axis and positive power is composed of a single lens or a plurality of lenses. In the lens system having an optical axis, when the lens system is composed of a plurality of lenses, the optical axes of the plurality of lenses constituting the lens system are completely or substantially coaxial, and the plurality of lenses constituting the lens system It means that there is no or substantially no shift or tilt of the optical axis of the lens. The lens system having positive power includes at least one lens having positive power, but may include lenses having negative power as long as the entire lens system has positive power. In order to correct or reduce the aberration of the imaging optical system, the lens system preferably includes both a lens having a positive power and a lens having a negative power. Further, the lenses included in the lens system having positive power may be either spherical lenses or aspherical lenses. When the lens system having a positive power includes an aspheric lens, the aberration of the imaging optical system can be reduced or corrected better. As a result, it is possible to provide an image reading apparatus including an imaging optical system having better resolution performance. Further, the number of lenses included in the lens system having positive power is not particularly limited, and is appropriately selected depending on the balance between the optical performance and cost of the imaging optical system included in the image reading apparatus.

  In this case, a smaller image reading apparatus can be provided more easily. In particular, the first optical system includes a reflective surface having a positive power, and the second optical system includes a lens system having an optical axis and a positive power. An imaging optical system in which an intermediate image that is a real image is formed in the optical path between the first optical system and the second optical system can be obtained more easily. Thus, since an intermediate image is formed in the optical path between the first optical system and the second optical system, it is easier to provide the first optical system including a reflecting surface having a large positive power. Is possible. As a result, it is possible to more easily provide a relatively wide-angle imaging optical system with a relatively short distance between object images.

  In the image reading apparatus according to the first embodiment of the present invention, preferably, the imaging optical system includes at least one reflecting surface that folds an optical path from the image to the imaged image and has no power. Is further included.

  Here, the reflecting surface having no power means a reflecting surface having no power or substantially no power. In other words, a reflective surface having no power means a fully or substantially planar reflective surface.

  In this case, it is possible to provide a smaller image reading apparatus. That is, the imaging optical system further includes at least one reflecting surface that folds the optical path from the image to the imaged image and does not have power. By folding the optical path, the size of the imaging optical system in the direction perpendicular to the image can be reduced. As a result, the size of the image reading device in the direction perpendicular to the image can be reduced.

  The image reading apparatus according to the first embodiment of the present invention is preferably configured such that the at least one reflecting surface that folds an optical path from the image to the imaged image and has no power is from the image. An image reading apparatus comprising at least one reflecting surface that folds an optical path to a reflecting surface having positive power and has no power.

  Here, when the number of reflection surfaces having positive power is plural, the optical path from the image to the reflection surface having positive power is from the image to the reflection surface having positive power closest to the image. Means the optical path.

  In this case, it is possible to provide a smaller image reading apparatus. That is, the at least one reflecting surface that folds the optical path from the image to the image formed and has no power folds the optical path from the image to the reflecting surface having the positive power and has power. Since it includes at least one reflecting surface that is not provided, the size of the imaging optical system in the direction perpendicular to the image is significantly reduced by folding the optical path from the image to the reflecting surface having a positive power. It becomes possible. As a result, the size of the image reading device in the direction perpendicular to the image can be significantly reduced.

  The image reading apparatus according to the first embodiment of the present invention preferably folds the optical path from the image to the reflective surface having the positive power and out of the at least one reflective surface having no power. The reflective surface that does not have the power closest to the reflective surface having the power of The image reading apparatus is arranged at a position at.

  Here, “a reflecting surface having no power closest to the reflecting surface having the positive power has a position at the position of the intermediate image or the positive power of the intermediate image with respect to the direction of the optical axis of the lens system. It is arranged at a position between the lens system and the lens system that has a positive power, the intersection of the lens system optical axis and the reflection surface that does not have the closest power to the lens surface optical axis. The intersection of the lens system having the positive power closest to the position of the intermediate image or the position of the intermediate image on the optical axis of the lens system and the position of the intermediate image on the optical axis of the lens system and the optical axis of the lens system Means that it exists at a position in between.

  In this case, it is possible to obtain an image reading apparatus capable of obtaining a relatively bright imaged image or a relatively high resolution performance imaged image.

  More specifically, the reflecting surface that does not have the power closest to the reflecting surface having the positive power has a power at the position of the intermediate image or the positive power with respect to the direction of the optical axis of the lens system. From a reflective surface having a positive power to an intermediate image, which can be caused by a reflective surface that is otherwise closest to the reflective surface having a positive power Vignetting of light, and from a reflective surface that has no power closest to a reflective surface with positive power, which may otherwise be caused by a lens system with positive power, to a reflective surface with positive power It is possible to reduce or avoid the vignetting of the light beam, and to reduce or avoid the vignetting of the light beam from the image to the image formed. As a result, it is possible to effectively form a light beam from the image to the image formed by the image sensor, and to obtain an image reading apparatus capable of obtaining a relatively bright image formed. Is possible.

  Alternatively, in order to reduce or avoid the vignetting of the light beam from the image to the image formed as described above, the tilt of the reflecting surface having a positive power with respect to the optical axis of the lens system and / or the shift of the image sensor However, in this case, the aberration of the imaging optical system tends to increase. A reflecting surface having no power closest to the reflecting surface having the positive power is located at the position of the intermediate image or the lens system having the positive power with respect to the direction of the optical axis of the lens system; Since the vignetting of the light beam from the image to the image formed as described above can be reduced or avoided, the positive power with respect to the optical axis of the lens system can be reduced. It is possible to reduce the tilt of the reflecting surface having the light and / or the shift of the image sensor. As a result, the aberration of the imaging optical system is reduced, and it is possible to obtain an image reading apparatus that can obtain an imaged image with relatively high resolution performance.

  The image reading apparatus according to the first embodiment of the present invention preferably folds the optical path from the image to the reflective surface having the positive power and out of the at least one reflective surface having no power. An image characterized in that a reflection surface that has no power closest to a reflection surface having a power of is arranged at an entrance pupil position of any light ray that enters the reflection surface having a positive power from the image. It is a reading device.

  Here, “the reflecting surface that does not have the power closest to the reflecting surface having the positive power is disposed at the entrance pupil position of any light ray that enters the reflecting surface having the positive power from the image. "It means that the principal ray (the center of the aperture stop of the imaging optical system or the entrance pupil) is incident on a reflecting surface that is emitted from all off-axis points in the image with respect to the optical axis of the lens system and has a positive power. The intersection of the reflecting surface that does not have the power closest to the reflecting surface having the positive power and the optical axis of the lens system exists within the range of the position where the light beam passing through the center intersects the optical axis of the lens system. It means to do.

  In this case, it is possible to provide an image reading apparatus including a smaller imaging optical system. More specifically, the reflecting surface that does not have the power closest to the reflecting surface having the positive power is disposed at the entrance pupil position of any light ray that enters the reflecting surface having the positive power from the image. Therefore, the reflecting surface that does not have the power closest to the reflecting surface having the positive power may be arranged at a position where the light rays emitted from the points in the image and incident on the reflecting surface having the positive power are relatively dense. It becomes possible. At this time, the reflecting surface that does not have the power closest to the reflecting surface having the positive power is only required to reflect the relatively dense light beams emitted from the points in the image. It is possible to reduce the size of the reflecting surface that does not have the closest power. Accordingly, a smaller imaging optical system can be provided.

  The image reading apparatus according to the first embodiment of the present invention is preferably an image reading apparatus characterized in that the number of lenses having power constituting the lens system is 3 or more and 6 or less. Further, the number of lenses having power constituting the lens system is more preferably 4 or more and 6 or less, and further preferably 4 or 5. Here, the lens having power includes a lens having positive power and / or a lens having negative power, but the lens system is designed to have positive power.

  In this case, it is possible to provide an image reading apparatus including an imaging optical system having a relatively simple configuration and relatively good resolution performance. That is, since the number of lenses having power constituting the lens system is 3 or more and 6 or less, an image including a relatively small number of lenses and having relatively good resolution performance is included. An optical system can be provided.

  The image reading apparatus according to the first embodiment of the present invention is preferably an image in which the image plane of the intermediate image is curved so as to approach the lens system as the distance from the optical axis of the lens system increases. It is a reading device.

  In this case, it is possible to provide an image reading apparatus including an imaging optical system having a relatively good resolution performance. That is, the image plane of the intermediate image is curved so as to be closer to the lens system as it is away from the optical axis of the lens system, so that it is generated by a reflecting surface having a positive power and is away from the optical axis of the lens system. The field curvature of the intermediate image closer to the lens system can be reduced or canceled by the field curvature generated by the lens system with positive power, reducing or eliminating the field curvature of the imaging optical system It becomes possible to do. As a result, it is possible to provide an imaging optical system having a relatively good resolution performance. In addition, since it becomes possible to reduce or eliminate the curvature of field of the imaging optical system, it is possible to provide an imaging optical system with a wider angle (with a larger viewing angle).

  The image reading apparatus according to the first embodiment of the present invention is preferably the image reading apparatus characterized in that the reflection surface having the positive power has an anamorphic aspherical shape. Note that the anamorphic aspheric shape may also be referred to as an anamorphic free-form shape.

Here, the shape of the anamorphic aspheric surface is, for example, the formula:
Z (x, y) = c · r 2 / [1 + √ {1− (1 + k) c 2 r 2 }] + X4Y0 · x 4 + X2Y2 · x 2 y 2 + X0Y4 · y 4 + X5Y0 · x 5 + X3Y2 · x 3 y 2 + X1Y4 · x 1 y 4 + X6Y0 · x 6 + X4Y2 · x 4 y 2 + X2Y4 · x 2 y 4 + X0Y6 · y 6 +
It is the shape of the surface represented by.

However, in the above formula, when the direction of the normal line of the anamorphic aspheric surface at the center (surface vertex) of the anamorphic aspheric surface is the z direction,
x is a coordinate in a first direction orthogonal to the z direction;
y is the coordinate in the second direction orthogonal to both the z direction and the first direction;
r is the height (r 2 = x 2 + y 2 ) in the direction perpendicular to the z direction,
Z (x, y) is a distance (sag amount) from the tangential plane of the center of the anamorphic aspheric surface to the anamorphic aspheric surface at the coordinates (x, y).
c is the curvature of the anamorphic aspheric surface at the center of the anamorphic aspheric surface (or the inverse of the radius of curvature);
k is the cone coefficient of the anamorphic aspheric surface at the center of the anamorphic aspheric surface,
X4Y0, X2Y2, X0Y4, X5Y0, X3Y2 ··· , respectively, term x 4, x 2 y 2 terms, term of y 4, the term x 5, with the coefficient of the term ... of x 3 y 2 is there.

  In this case, it is possible to provide an image reading apparatus including an imaging optical system having a relatively good resolution performance. That is, since the reflecting surface having the positive power has an anamorphic aspherical shape, the degree of freedom in designing the reflecting surface having the positive power is increased, and the aberration of the imaging optical system is improved. It becomes possible to correct or reduce. As a result, it is possible to provide an imaging optical system having a relatively good resolution performance. In particular, it becomes possible to correct or reduce distortion and / or field curvature, which can often occur significantly in a relatively wide-angle imaging optical system, and a relatively wide-angle with relatively good resolution performance. An imaging optical system can be obtained.

  In the image reading apparatus according to the first embodiment of the present invention, preferably, the imaging element has pixels arranged in at least a first direction, and the first direction with respect to the optical axis of the lens system. And an image reading apparatus that is shifted in a direction perpendicular to both directions of the optical axis of the lens system.

  Here, the first direction in the pixels arranged in at least the first direction means one of at least one direction in which the pixels in the image sensor are arranged. For example, when the image sensor is a one-dimensional image sensor, the first direction is a direction in which pixels in the one-dimensional image sensor are arranged. Further, when the image sensor is a two-dimensional image sensor, it is one of two directions in which pixels in the two-dimensional image sensor are arranged. In particular, when the two-dimensional image sensor has pixels arranged in the longitudinal direction and the lateral direction, the first direction is usually the longitudinal direction.

  In this case, it is possible to more easily provide an image reading apparatus including a smaller imaging optical system. More specifically, particularly when the first optical system includes a reflecting surface having a positive power and the second optical system includes a lens system having an optical axis and having a positive power, the result is obtained from an image. In order to avoid or reduce the vignetting of the light beam up to the imaged image by the lens system and / or the imaging device having the positive power, the light beam incident on the reflecting surface having the positive power from the image and the positive light It is necessary to partially separate the light rays that exit from the reflecting surface having the power of (2) toward the lens system having the positive power (avoid matching completely). For this purpose, it is conceivable to tilt the reflecting surface having positive power with respect to the optical axis of the lens system having positive power and / or to shift the image sensor. Here, the imaging device has pixels arranged in at least a first direction and is perpendicular to both the first direction and the direction of the optical axis of the lens system with respect to the optical axis of the lens system. The light beam incident on the reflecting surface having positive power from the image and the light beam exiting from the reflecting surface having positive power toward the lens system having positive power can be more easily divided. Separation becomes possible. Accordingly, it is possible to more easily arrange the optical elements constituting the imaging optical system such as the reflecting surface having positive power and the lens system having positive power. That is, it is easier to provide an imaging optical system in which the first optical system includes a reflecting surface having positive power and the second optical system includes a lens system having an optical axis and positive power. It becomes possible.

  In the image reading apparatus according to the first embodiment of the present invention, preferably, the imaging element has pixels arranged in at least a first direction, and the first direction and the optical axis of the lens system. The length of the reflecting surface having the positive power in the direction perpendicular to both of the directions is not more than half of the length of the reflecting surface having the positive power in the first direction. An image reading apparatus. The length of the reflecting surface having the positive power in the direction perpendicular to both the first direction and the direction of the optical axis of the lens system more preferably has the positive power in the first direction. It is 1/5 or less of the length of a reflective surface, More preferably, it is 1/10 or less.

  The configuration of “the image sensor has pixels arranged at least in the first direction” is the same as that described above.

  In this case, it is possible to more easily provide an image reading apparatus including a smaller imaging optical system. That is, the length of the reflecting surface having the positive power in the direction perpendicular to both the first direction and the direction of the optical axis of the lens system is the reflecting surface having the positive power in the first direction. Therefore, it is possible to reduce the size of the reflecting surface having a positive power, and to provide a smaller imaging optical system.

  In the image reading apparatus according to the first embodiment of the present invention, preferably, the imaging element has pixels arranged in at least a first direction, and the image is formed from the image in the first direction. The length of the at least one reflecting surface that folds the optical path to the image formed and has no power is smaller than the length of the reflecting surface having the positive power in the first direction. An image reading apparatus.

  The configuration of “the image sensor has pixels arranged at least in the first direction” is the same as that described above.

  In this case, it is possible to more easily provide an image reading apparatus including a smaller imaging optical system. That is, the length of the at least one reflecting surface that folds the optical path from the image to the image formed in the first direction and has no power is the positive length in the first direction. Since it is smaller than the length of the reflecting surface having power, it is possible to reduce the size of at least one reflecting surface having no power, and to provide a smaller imaging optical system.

  According to a second embodiment of the present invention, there is provided an image reading method for reading image information, the method including reading image information using the image reading apparatus according to the first embodiment of the present invention. This is a reading method.

  According to the second embodiment of the present invention, since the image reading apparatus according to the first embodiment of the present invention capable of providing a smaller image reading apparatus is used, a smaller image reading apparatus is provided. It is possible to provide an image reading method using the.

  According to a third embodiment of the present invention, in an image forming apparatus for forming an image on an image carrier, the image reading apparatus according to the first embodiment of the present invention and information on an image read by the image reading apparatus are used. An image forming apparatus comprising a device for forming an image on the image carrier.

  Here, the image in forming the image on the image carrier may be the same as or different from the image read by the image reading apparatus. The image carrier may be, for example, a photoreceptor or a recording medium such as paper and plastic sheets. Further, the image formed on the image carrier may be an electrostatic latent image or an image of a developer obtained by developing the electrostatic latent image with a developer containing toner. In addition, a device for forming an image on the image bearing member includes a charging unit for charging the photosensitive member, an exposure unit (optical writing unit) for writing an electrostatic latent image on the charged photosensitive member such as an optical scanning device, and a photosensitive member. Development means for developing the formed electrostatic latent image with a developer, transfer means for transferring an image of the developed developer to a recording medium, cleaning means for removing the developer remaining on the photoreceptor, and / or photosensitivity It may include known devices such as those used in electrophotographic processes, such as static elimination means for initializing body potential.

  According to the third embodiment of the present invention, since the image reading apparatus according to the first embodiment of the present invention capable of providing a smaller image reading apparatus is included, a smaller image reading apparatus is included. An image forming apparatus can be provided. As a result, a smaller image reading apparatus can be provided.

  The fourth embodiment of the present invention includes, in an image forming method for forming an image on an image carrier, forming an image on the image carrier using the image forming apparatus according to the third embodiment of the present invention. This is an image forming method.

  According to the fourth embodiment of the present invention, the image forming apparatus according to the third embodiment of the present invention that can provide an image forming apparatus including a smaller image reading apparatus is used. It is possible to provide an image forming method using an image forming apparatus including the image reading apparatus.

  According to a fifth embodiment of the present invention, in an imaging optical system that forms an object on an image, a first optical system that forms the object on an intermediate image and a second optical system that forms the intermediate image on the image An image forming optical system including the following optical system.

  Here, the imaging includes both imaging on an image having no aberration and imaging on an image having aberration. In other words, the image includes both an image without aberration and an image with aberration. The object and the intermediate image are conjugated with respect to the first optical system, the intermediate image and the image are conjugated with respect to the second optical system, and the object and the image are conjugated with respect to the imaging optical system. There is a relationship. The object is not particularly limited. In the fifth embodiment of the present invention, the term “image” is not an intermediate image, but an image obtained by forming an intermediate image with the second optical system.

  According to the fifth embodiment of the present invention, a smaller imaging optical system can be provided. In particular, according to the fifth embodiment of the present invention, an imaging optical system that forms an object on an image includes a first optical system that forms the object on an intermediate image and the intermediate image on the image. Since the second optical system to be imaged is included, that is, an intermediate image is formed, the first optical system having a large power can be provided. As a result, it is possible to provide a relatively wide-angle imaging optical system having a relatively short distance between object images. For example, since the distance between the object images of the imaging optical system is relatively short, the optical path length from the object to the first optical system can be reduced. Further, even when the optical path from the object to the first optical system is folded by a reflecting surface without power, the number of folding or the number of reflecting surfaces without power can be reduced. . As a result, the manufacturing cost of the reflecting surface without power, such as processing and vapor deposition of the reflecting surface without power, and the power for installing the reflecting surface without power in the imaging optical system are provided. This makes it possible to reduce the time and effort for adjusting the position of the reflecting surface that is not to be set.

  The imaging optical system according to the fifth embodiment of the present invention can be used, for example, in a reading optical system included in a document reading section of a facsimile and a digital copying machine and various image scanners.

  In the imaging optical system according to the fifth embodiment of the present invention, preferably, the first optical system includes a reflecting surface having a positive power, and the second optical system has an optical axis. And an imaging optical system including a lens system having positive power.

  Here, the reflecting surface having positive power specifically means a concave reflecting surface. Further, the shape of the reflecting surface having positive power may be either a spherical shape or an aspherical shape. However, in order to correct or reduce the aberration of the imaging optical system, it is preferable that the reflecting surface has an axisymmetric aspherical surface. Shape and aspheric shape such as anamorphic aspheric shape. Further, the number of reflecting surfaces having positive power may be one or plural, but is preferably one in order to reduce the size of the configuration of the imaging optical system.

  A lens system having an optical axis and positive power is composed of a single lens or a plurality of lenses. In the lens system having an optical axis, when the lens system is composed of a plurality of lenses, the optical axes of the plurality of lenses constituting the lens system are completely or substantially coaxial, and the plurality of lenses constituting the lens system It means that there is no or substantially no shift or tilt of the optical axis of the lens. The lens system having positive power includes at least one lens having positive power, but may include lenses having negative power as long as the entire lens system has positive power. In order to correct or reduce the aberration of the imaging optical system, the lens system preferably includes both a lens having a positive power and a lens having a negative power. Further, the lenses included in the lens system having positive power may be either spherical lenses or aspherical lenses. When the lens system having a positive power includes an aspheric lens, the aberration of the imaging optical system can be reduced or corrected better. As a result, it is possible to provide an imaging optical system having better resolution performance. Further, the number of lenses included in the lens system having a positive power is not particularly limited, and is appropriately selected depending on the balance of optical performance and cost of the imaging optical system.

  In this case, a smaller imaging optical system can be provided more easily. In particular, the first optical system includes a reflective surface having a positive power, and the second optical system includes a lens system having an optical axis and a positive power. An imaging optical system in which an intermediate image that is a real image is formed in the optical path between the first optical system and the second optical system can be obtained more easily. Thus, since an intermediate image is formed in the optical path between the first optical system and the second optical system, it is easier to provide the first optical system including a reflecting surface having a large positive power. Is possible. As a result, it is possible to more easily provide a relatively wide-angle imaging optical system with a relatively short distance between object images.

  In the imaging optical system according to the fifth embodiment of the present invention, preferably, the imaging optical system further includes at least one reflecting surface that folds an optical path from the object to the image and has no power. This is an imaging optical system characterized by the above.

  Here, the reflecting surface having no power means a reflecting surface having no power or substantially no power. In other words, a reflective surface having no power means a fully or substantially planar reflective surface.

  In this case, it is possible to provide a further compact imaging optical system. That is, the imaging optical system further includes at least one reflecting surface that folds the optical path from the object to the image and does not have power, so that by folding the optical path from the object to the image, It is possible to reduce the size of the imaging optical system in the vertical direction. As a result, it is possible to reduce the size of the imaging optical system in the direction perpendicular to the object.

  In the imaging optical system according to the fifth embodiment of the present invention, preferably, the at least one reflecting surface that folds an optical path from the object to the image and does not have power has the positive power from the object. An imaging optical system characterized in that it includes at least one reflecting surface that folds the optical path to the reflecting surface and has no power.

  Here, when the number of reflecting surfaces having positive power is plural, the optical path from the object to the reflecting surface having positive power is from the object to the reflecting surface having positive power closest to the object. Means the optical path.

  In this case, it is possible to provide a further compact imaging optical system. That is, the at least one reflecting surface that folds the optical path from the object to the image and does not have power is at least one that folds the optical path from the object to the reflecting surface having positive power and does not have power. Since it includes two reflecting surfaces, it is possible to significantly reduce the size of the imaging optical system in a direction perpendicular to the object by folding the optical path from the object to the reflecting surface having a positive power. . As a result, the size of the imaging optical system in the direction perpendicular to the object can be significantly reduced.

  The imaging optical system according to the fifth embodiment of the present invention preferably folds the optical path from the object to the reflecting surface having the positive power and has at least one of the reflecting surfaces having no power. The reflecting surface that has no power closest to the reflecting surface having the positive power is located at the position of the intermediate image or the lens system having the positive power with respect to the direction of the optical axis of the lens system. It is an imaging optical system characterized by being arranged in the position between.

  Here, “a reflecting surface having no power closest to the reflecting surface having the positive power has a position at the position of the intermediate image or the positive power of the intermediate image with respect to the direction of the optical axis of the lens system. It is arranged at a position between the lens system and the lens system that has a positive power, the intersection of the lens system optical axis and the reflection surface that does not have the closest power to the lens surface optical axis. The intersection of the lens system having the positive power closest to the position of the intermediate image or the position of the intermediate image on the optical axis of the lens system and the position of the intermediate image on the optical axis of the lens system and the optical axis of the lens system Means that it exists at a position in between.

  In this case, it is possible to obtain an imaging optical system that can obtain a relatively bright image or an image with relatively high resolution performance.

  More specifically, the reflecting surface that does not have the power closest to the reflecting surface having the positive power has a power at the position of the intermediate image or the positive power with respect to the direction of the optical axis of the lens system. From a reflective surface having a positive power to an intermediate image, which can be caused by a reflective surface that is otherwise closest to the reflective surface having a positive power Vignetting of light, and from a reflective surface that has no power closest to a reflective surface with positive power, which may otherwise be caused by a lens system with positive power, to a reflective surface with positive power It is possible to reduce or avoid the vignetting of the light beam from the object, and it is possible to reduce or avoid the vignetting of the light beam from the object to the image. As a result, it is possible to more effectively form light rays from the object to the image, and an imaging optical system capable of obtaining a relatively bright image can be obtained.

  Alternatively, in order to reduce or avoid the vignetting of the light beam from the object to the image as described above, the tilt of the reflecting surface having a positive power with respect to the optical axis of the lens system and / or the shift of the image surface may be increased. In this case, the aberration of the imaging optical system tends to increase. A reflecting surface having no power closest to the reflecting surface having the positive power is located at the position of the intermediate image or the lens system having the positive power with respect to the direction of the optical axis of the lens system; If it is arranged at a position in between, it becomes possible to reduce or avoid the vignetting of the ray from the object to the image as described above, so that the reflecting surface having a positive power with respect to the optical axis of the lens system It is possible to reduce tilt and / or image plane shift. As a result, the aberration of the imaging optical system is reduced, and an imaging optical system capable of obtaining an image with relatively high resolution performance can be obtained.

  The imaging optical system according to the fifth embodiment of the present invention preferably folds the optical path from the object to the reflecting surface having the positive power and has at least one of the reflecting surfaces having no power. The reflecting surface that does not have power closest to the reflecting surface having positive power is disposed at the entrance pupil position of any light ray that enters the reflecting surface having positive power from the object. This is an imaging optical system.

  Here, “the reflecting surface that does not have the power closest to the reflecting surface having the positive power is arranged at the entrance pupil position of any light ray that enters the reflecting surface having the positive power from the object. "It means that the chief rays (at the center of the aperture stop or entrance pupil of the imaging optical system) that are emitted from all off-axis points in the object with respect to the optical axis of the lens system and are incident on the reflecting surface having positive power. The intersection of the reflecting surface that does not have the power closest to the reflecting surface having the positive power and the optical axis of the lens system exists within the range of the position where the light beam passing through the center intersects the optical axis of the lens system. It means to do.

  In this case, a smaller imaging optical system can be provided. More specifically, the reflecting surface that does not have the power closest to the reflecting surface having the positive power is disposed at the entrance pupil position of any light ray that enters the reflecting surface having the positive power from the object. Therefore, it is possible to arrange the reflecting surface that does not have the power closest to the reflecting surface having the positive power at a position where the light rays emitted from the point on the object and incident on the reflecting surface having the positive power are relatively dense. It becomes possible. At this time, the reflecting surface that does not have the power closest to the reflecting surface having the positive power may reflect the relatively dense light beams emitted from the points in the object, and thus the reflecting surface having the positive power. It is possible to reduce the size of the reflecting surface that does not have the closest power. Accordingly, a smaller imaging optical system can be provided.

  In the imaging optical system according to the fifth embodiment of the present invention, preferably, the number of lenses having power constituting the lens system is 3 or more and 6 or less. It is. Further, the number of lenses having power constituting the lens system is more preferably 4 or more and 6 or less, and further preferably 4 or 5. Here, the lens having power includes a lens having positive power and / or a lens having negative power, but the lens system is designed to have positive power.

  In this case, it is possible to provide an imaging optical system having a relatively simple configuration and relatively good resolution performance. That is, since the number of lenses having power constituting the lens system is 3 or more and 6 or less, an image including a relatively small number of lenses and having relatively good resolution performance is included. An optical system can be provided.

  The imaging optical system according to the fifth embodiment of the present invention is preferably characterized in that the image plane of the intermediate image is curved so as to approach the lens system as the distance from the optical axis of the lens system increases. This is an imaging optical system.

  In this case, it is possible to provide an imaging optical system having a relatively good resolution performance. That is, the image plane of the intermediate image is curved so as to be closer to the lens system as it is away from the optical axis of the lens system, so that it is generated by a reflecting surface having a positive power and is away from the optical axis of the lens system. The field curvature of the intermediate image closer to the lens system can be reduced or canceled by the field curvature generated by the lens system with positive power, reducing or eliminating the field curvature of the imaging optical system It becomes possible to do. As a result, it is possible to provide an imaging optical system having a relatively good resolution performance. In addition, since it becomes possible to reduce or eliminate the curvature of field of the imaging optical system, it is possible to provide an imaging optical system with a wider angle (with a larger viewing angle).

  The imaging optical system according to the fifth embodiment of the present invention is preferably an imaging optical system characterized in that the reflecting surface having positive power has an anamorphic aspherical shape. . Note that the anamorphic aspheric shape may also be referred to as an anamorphic free-form shape.

Here, the shape of the anamorphic aspheric surface is, for example, the formula:
Z (x, y) = c · r 2 / [1 + √ {1− (1 + k) c 2 r 2 }] + X4Y0 · x 4 + X2Y2 · x 2 y 2 + X0Y4 · y 4 + X5Y0 · x 5 + X3Y2 · x 3 y 2 + X1Y4 · x 1 y 4 + X6Y0 · x 6 + X4Y2 · x 4 y 2 + X2Y4 · x 2 y 4 + X0Y6 · y 6 +
It is the shape of the surface represented by.

However, in the above formula, when the direction of the normal line of the anamorphic aspheric surface at the center (surface vertex) of the anamorphic aspheric surface is the z direction,
x is a coordinate in a first direction orthogonal to the z direction;
y is the coordinate in the second direction orthogonal to both the z direction and the first direction;
r is the height (r 2 = x 2 + y 2 ) in the direction perpendicular to the z direction,
Z (x, y) is a distance (sag amount) from the tangential plane of the center of the anamorphic aspheric surface to the anamorphic aspheric surface at the coordinates (x, y).
c is the curvature of the anamorphic aspheric surface at the center of the anamorphic aspheric surface (or the inverse of the radius of curvature);
k is the cone coefficient of the anamorphic aspheric surface at the center of the anamorphic aspheric surface,
X4Y0, X2Y2, X0Y4, X5Y0, X3Y2 ··· , respectively, term x 4, x 2 y 2 terms, term of y 4, the term x 5, with the coefficient of the term ... of x 3 y 2 is there.

  In this case, it is possible to provide an imaging optical system having a relatively good resolution performance. That is, since the reflecting surface having the positive power has an anamorphic aspherical shape, the degree of freedom in designing the reflecting surface having the positive power is increased, and the aberration of the imaging optical system is improved. It becomes possible to correct or reduce. As a result, it is possible to provide an imaging optical system having a relatively good resolution performance. In particular, it becomes possible to correct or reduce distortion and / or field curvature, which can often occur significantly in a relatively wide-angle imaging optical system, and a relatively wide-angle with relatively good resolution performance. An imaging optical system can be obtained.

  In the imaging optical system according to the fifth embodiment of the present invention, preferably, the image is shifted in a direction perpendicular to an optical axis direction of the lens system with respect to an optical axis of the lens system. An imaging optical system characterized by the following.

  In this case, a smaller imaging optical system can be provided more easily. More specifically, an image from an object, particularly when the first optical system includes a reflecting surface having a positive power and the second optical system includes a lens system having an optical axis and having a positive power. In order to avoid or reduce vignetting by a lens system having a positive power, the light beam incident on the reflecting surface having the positive power and the reflecting surface having the positive power from the object are positive. It is necessary to partially separate the light rays that are emitted towards the lens system with power (to avoid perfect matching). For this purpose, it is conceivable to tilt the reflecting surface having positive power with respect to the optical axis of the lens system having positive power and / or shift the image surface. Here, the image is shifted in a direction perpendicular to the direction of the optical axis of the lens system with respect to the optical axis of the lens system. It is possible to more easily and partially separate the light beam emitted from the reflecting surface having the power of 1 to the lens system having the positive power. Accordingly, it is possible to more easily arrange the optical elements constituting the imaging optical system such as the reflecting surface having positive power and the lens system having positive power. That is, it is easier to provide an imaging optical system in which the first optical system includes a reflecting surface having positive power and the second optical system includes a lens system having an optical axis and positive power. It becomes possible.

  In the imaging optical system according to the fifth embodiment of the present invention, preferably, the length of the reflecting surface having the positive power in the first direction perpendicular to the direction of the optical axis of the lens system is the lens. An imaging optical system characterized in that the length is less than half of the length of the reflecting surface having the positive power in a direction perpendicular to both the direction of the optical axis of the system and the first direction. The length of the reflecting surface having the positive power in the first direction perpendicular to the direction of the optical axis of the lens system is more preferably in both the direction of the optical axis of the lens system and the first direction. It is one fifth or less of the length of the reflecting surface having the positive power in the vertical direction, and more preferably one tenth or less.

  In this case, a smaller imaging optical system can be provided more easily. That is, the length of the reflecting surface having the positive power in the first direction perpendicular to the direction of the optical axis of the lens system is perpendicular to both the direction of the optical axis of the lens system and the first direction. Since it is less than half the length of the reflecting surface having the positive power in the direction, it is possible to reduce the size of the reflecting surface having the positive power and to provide a smaller imaging optical system. It becomes possible to do.

  The imaging optical system according to the fifth embodiment of the present invention preferably folds the optical path from the object to the image and has power in a first direction perpendicular to the direction of the optical axis of the lens system. The imaging optical system is characterized in that a length of the at least one reflecting surface is smaller than a length of the reflecting surface having the positive power in the first direction.

  In this case, a smaller imaging optical system can be provided more easily. That is, in the first direction perpendicular to the optical axis direction of the lens system, the length of the at least one reflecting surface that folds the optical path from the object to the image and has no power is the first length. Since it is smaller than the length of the reflecting surface having the positive power in the direction, it is possible to reduce the size of at least one reflecting surface having no power, and to provide a smaller imaging optical system Is possible.

[Example 1]
FIG. 1 is a diagram illustrating an example of an imaging optical system in an image reading apparatus according to an embodiment of the present invention. FIG. 1A is a diagram illustrating an example of an imaging optical system in an image reading apparatus according to an embodiment of the present invention, and FIG. 1B is an imaging optical system in a conventional image reading apparatus. It is a figure which shows one example of.

  In one example of the imaging optical system 100 or 100 ′ in the image reading apparatus shown in FIG. 1A and FIG. 1B, the document surface 101 or 101 ′ on the object surface, positive, in order from the object side. A reflecting surface 102 or 102 ′ having power, a lens system 103 or 103 ′ having positive power, and an image sensor 104 or 104 ′ on the image surface are arranged. However, in FIGS. 1 (a) and 1 (b), the reflecting surface 102 or 102 ′ having a positive power is schematically shown in order to avoid overlapping of light rays and more easily explain the imaging optical system. It is depicted as a refractive lens. Further, the lens system 103 or 103 ′ having a positive power is schematically drawn with one lens, but in the image reading apparatus according to one embodiment of the present invention as shown in FIG. In the example of the imaging optical system 100, the lens system is not limited to a lens system including only one lens, and may be a lens group including a plurality of lenses.

  In the example of the imaging optical system 100 in the image reading apparatus according to the embodiment of the present invention as shown in FIG. 1A, the luminous flux of each angle of view emitted from each point of the document surface 101 is positive. The convergent light beams once collected before being incident on the reflecting surface 102 having power and refracted by the reflecting surface 102 having positive power are substantially converged to form an intermediate image 105. That is, the entrance pupil 106 of the imaging optical system 100 shown in FIG. 1A exists between the original surface 101 and the reflecting surface 102 having a positive power, and the principal ray of the light beam emitted from the original surface 101. Intersect in the vicinity of the position of the entrance pupil 106. A divergent light beam from the intermediate image 105 formed by the reflecting surface 102 having a positive power is focused on the image sensor 104 by a lens system 103 having a positive power provided with an aperture stop. An image of the original surface is formed on 104. Here, since the intermediate image 105 is formed between the reflecting surface 102 having positive power and the lens system 103 having positive power, the reflecting surface 102 having positive power can have a large power. . As a result, the imaging optical system 100 shown in FIG. 1A can be more easily designed as a wide-angle optical system. In addition, the configuration of the lens system 103 having a positive power provided between the intermediate image 105 and the image sensor 104 is the aberration generated by the reflecting surface 102 having the positive power, particularly the viewing angle of the optical system. If the optimization is performed so as to correct distortion, curvature of field, and astigmatism due to the increase in, the aberration of the final image plane, that is, the image plane on the image sensor 104 is corrected satisfactorily. As a result, the resolution performance of the imaging optical system 100 is improved, and a wider-angle imaging optical system 100 can be obtained.

  On the other hand, in the example of the imaging optical system 100 ′ in the conventional image reading apparatus as shown in FIG. 1B, between the reflecting surface 102 ′ having positive power and the lens system 103 ′ having positive power. Therefore, it is difficult for the reflecting surface 102 ′ having a positive power to have a large power. As a result, it is difficult to obtain a wide-angle imaging optical system 100 ′.

  As shown in FIG. 1A, in order from the object side, a document surface 101 on the object surface, a reflecting surface 102 having a positive power, a lens system 103 having a positive power, and an image sensor 104 on the image surface are arranged. In the image reading apparatus including the imaging optical system 100, a wide-angle imaging optical system is formed by forming an intermediate image 105 between the reflecting surface 102 having positive power and the lens system 103 having positive power. An image reading apparatus including 100 can be obtained.

[Example 2]
FIG. 2 is a diagram illustrating another example of the imaging optical system in the image reading apparatus according to one embodiment of the present invention. More specifically, FIG. 2 shows a YZ section of the imaging optical system 200 in the X, Y, and Z directions orthogonal to each other. Here, the Y direction is the longitudinal direction of the pixel array of the image sensor 204 and is also called the main scanning direction of the image reading apparatus. The Z direction is the direction of the optical axis of the lens system 203 having positive power. That is, the optical axis of the lens system 203 having positive power and the longitudinal direction of the pixel array of the image sensor 204 are orthogonal to each other.

  In the image reading apparatus according to the embodiment of the present invention, the image sensor 204 may be a one-dimensional image sensor having a one-dimensional pixel. Alternatively, in order to read a color image, for example, in order to read signals of three colors of red, green, and blue, an image sensor in which three one-dimensional image sensors are arranged in parallel can be used. The main scanning direction of the image reading apparatus is the direction of the one-dimensional pixel array of the image sensor.

  An example of the imaging optical system 200 of the image reading apparatus according to one embodiment of the present invention as shown in FIG. 2 is arranged on the object plane along the optical path of the imaging optical system 200 in order from the object side. A document surface 201 of a document, a contact glass 207, a flat mirror 208 that folds the optical path, a reflective surface 202 having a positive power, a lens system 203 having a positive power, and an image sensor 204 arranged on the image surface. ing. Although not shown in FIG. 2, illumination means such as a lamp for irradiating the original surface 201 with light is often arranged. Reflected light from the document 201 illuminated by illumination means or the like enters the flat mirror 208 disposed near the entrance pupil 206 through the contact glass 207. Here, the optical path of the reflected light from the document surface 201 is folded by a plane mirror 208 disposed in the vicinity of the entrance pupil 206. Next, the light beam whose optical path is folded by the plane mirror 208 is incident on the reflecting surface 202 having a positive power, and the light beam of the convergent light refracted by the reflecting surface 202 having the positive power is substantially focused. Thus, an intermediate image 205 is formed. Here, the principal rays of the reflected light of each angle of view from the document surface 201 are collected in the vicinity of the entrance pupil 206 of the imaging optical system 200. For this reason, when the plane mirror 208 is disposed in the vicinity of the position of the entrance pupil 206 of the imaging optical system 200, the length of the plane mirror 208 in the Y direction is the power disposed closest to the object in the Y direction. This is smaller than the length of the reflecting surface 202 having a positive power as an optical element having, so that the area of the plane mirror 208 can be reduced. Next, a divergent light beam from the intermediate image 205 formed by the reflecting surface 202 having a positive power is focused on the image sensor 204 by a lens system 203 having a positive power provided with an aperture stop. An image of the original surface is formed on the image sensor 204.

  Here, by curving the image surface of the intermediate image 205, the field curvature generated by the reflecting surface 202 having a positive power is reduced, corrected or compensated by the field curvature of the lens system 203 having a positive power. can do. In particular, when the image plane of the intermediate image 205 is curved closer to the lens system 203 as it moves away from the optical axis of the lens system 203 having positive power, the power of the reflecting surface 202 having positive power is increased. Reduces the field curvature generated by the reflecting surface 202 having a positive power when the viewing angle of the imaging optical system 200 is increased by the field curvature of the lens system 203 having a positive power, or It becomes possible to compensate. As a result, the viewing angle of the imaging optical system 200 can be further increased.

  Further, when the reflecting surface 202 having positive power is an axisymmetric aspherical surface, the degree of freedom in designing the reflecting surface 202 having positive power can be increased, and the resolution performance of the imaging optical system can be increased. It becomes possible to improve. Furthermore, when the reflecting surface 202 having positive power has an anamorphic free-form shape, the degree of freedom in designing the reflecting surface 202 having positive power can be further increased. As a result, it is possible to obtain the imaging optical system 200 having high resolution performance. Further, since the aberration correction capability of the anamorphic free-form surface is high, it is possible to further increase the viewing angle of the imaging optical system 200 while maintaining the resolution performance of the imaging optical system 200.

[Example 3]
FIG. 3 is a diagram illustrating another example of the imaging optical system in the image reading apparatus according to one embodiment of the present invention. More specifically, FIG. 3 shows an XZ section of the imaging optical system 300 in the X, Y, and Z directions orthogonal to each other. Here, the Y direction and the Z direction are the same as those in the second embodiment. FIG. 3 is also a side view of the imaging optical system 200 shown in FIG.

  As in FIG. 3, the imaging optical system 300 includes, in order from the object side, the document surface (not shown) of the document placed on the object surface, contact glass (not shown), normal A plane mirror 308 closest to the reflecting surface 302 having a power of ## EQU2 ## a reflecting surface 302 having a positive power, a lens system 303 having a positive power, and an imaging device 304 disposed on the image plane. In the imaging optical system 300 shown in FIG. 3, a plane mirror 308 for folding the optical path is disposed in the optical path between the original surface of the original and the reflecting surface 302 having power, and the optical path is folded. The size of the imaging optical system 300 is reduced.

  In FIG. 3, A indicates the point where the uppermost light beam in the X direction among the light beams emitted from one point on the document surface hits the plane mirror 308 closest to the reflecting surface 102 having positive power, and B indicates Of the luminous fluxes emitted from one point on the document surface, the lowermost light beam in the X direction hits the flat mirror 308 closest to the reflecting surface 302 having positive power. C indicates a point where the uppermost ray in the X direction hits the reflecting surface 302 having positive power, and D indicates a point where the lowermost ray in the X direction hits the reflecting surface 302 having positive power. Show. E denotes the point where the lowest ray in the X direction hits the first surface of the lens system 303 having positive power, and F denotes the lens system in which the uppermost ray in the X direction has positive power. A point corresponding to the first face of 303 is shown.

  As shown in FIG. 3, among the light beams emitted from one point on the original surface, the uppermost light beam in the X direction passes along the ACF path, and X of the light beams emitted from one point on the original surface. The bottom ray in the direction passes along the BDE path. Further, the intersection of the line CF and the line DE is generally the position of the intermediate image 305.

  Here, for example, while maintaining the angle between the light beam BD and the light beam DE, the plane mirror 308 is reflected with a positive power with respect to the direction of the optical axis 320 of the lens system 303 with a positive power. If the plane mirror 308 is disposed between the surface 302 and the intermediate image 305, the plane mirror 308 intersects with the light beam CF and the like, and the light beam CF and the like is vignetted by the plane mirror 308.

  On the other hand, with respect to the direction of the optical axis 320 of the lens system 303 having a positive power, the plane mirror 308 is arranged to have a positive power with respect to the direction of the optical axis 320 of the lens system 303 having a positive power. Assuming that the light beam BD emitted from the plane mirror 308 intersects with the lenses constituting the lens system 303 having positive power, the light beam BD and the like are positive. The lens constituting the lens system 303 having power is vignetted.

  In order to avoid vignetting of the light beam CF or the like or the light beam BD, the angle between the light beam BD and the light beam DE is increased, that is, the positive power with respect to the direction of the optical axis 320 of the lens system 303 having a positive power. Increasing the inclination angle of the reflecting surface 302 having In this case, the position of the image sensor 304 is shifted upward in the X direction on the image plane, and the shift of the angle of view of the image sensor 304 with respect to the optical axis 320 is increased. Here, generally, when the shift of the angle of view of the image sensor 304 is increased, the aberration of the imaging optical system 300 increases, and the resolution performance of the imaging optical system 300 tends to deteriorate. Therefore, it is required to improve the aberration correction capability of optical elements such as the reflecting surface 302 and the lens system 303. For example, the number of lenses constituting the lens system 303 is increased, or an aspheric lens is used for the lens system 303. Will do. As a result, the cost of the imaging optical system 300 increases, and the assembly of the lens system 303 in the imaging optical system 300 becomes more complicated.

  Therefore, in the imaging optical system 300 shown in FIG. 3, while maintaining the angle between the light beam BD and the light beam DE as small as possible, the light beam CF or the like does not cross the plane mirror 108, or A plane mirror 308 with respect to the direction of the optical axis 320 of the lens system 303 having a positive power is indicated by an arrow in FIG. 3 so that the light beam BD or the like does not intersect with the lens constituting the lens system 303 having the positive power. Thus, it is between the intermediate image 305 and the lens system 303 having positive power. When the plane mirror 308 is disposed between the intermediate image 305 and the lens system 303 having positive power, the angle between the light beam BD and the light beam DE can be maintained at a small angle. The shift of the image sensor 304 with respect to the optical axis 320 of the lens system 303 can be reduced. As a result, it is possible to provide the imaging optical system 300 having reduced aberration and higher resolution performance.

[Example 4]
FIG. 4 is a diagram illustrating an example of an image reading apparatus according to an embodiment of the present invention. More specifically, FIG. 4 shows an XZ cross section of the image reading apparatus 400 in the X, Y, and Z directions orthogonal to each other. Here, the X direction is a direction perpendicular to the document surface 401 of the document from which an image is read, and in FIG. 4 is the height direction of the image reading device 400. The Z direction is a direction in which the traveling body of the image reading apparatus 400 travels when an image on the original surface 401 of the original is read, and is also referred to as a sub-scanning direction of the image reading apparatus 400. In FIG. This is the same direction as the direction of the optical axis 420 of the lens system 403 having a positive power constituting the imaging optical system included in the reading apparatus. The Y direction is the longitudinal direction of the pixel array of the image sensor 404 and is also called the main scanning direction of the image reading apparatus.

  Similarly to the second embodiment, in the image reading apparatus 400 shown in FIG. 4, a one-dimensional image sensor having one-dimensional pixels can be used as the image sensor 404. Alternatively, in order to read a color image, for example, in order to read signals of three colors of red, green, and blue, an image sensor in which three one-dimensional image sensors are arranged in parallel can be used. The main scanning direction of the image reading device 400 is the direction of the one-dimensional pixel array of the image sensor.

  In the image reading apparatus 400 shown in FIG. 4, the document surface 401 of the document placed on the contact glass 407 is illuminated by the illumination unit 415, and the optical path of the reflected light from the document surface 401 of the document is a plurality of plane mirrors 410. , 409, and the reflected light from the original surface 401 is incident on a flat mirror 408 disposed in the vicinity of the entrance pupil 406 of the imaging optical system and closest to the reflective surface 402 having a positive power. Next, the light reflected by the plane mirror 408 is reflected by the reflecting surface 402 having a positive power, and the luminous flux of each angle of view reflected by the reflecting surface 402 having the positive power is substantially focused, An intermediate image 405 is formed. The light beam diverging from the intermediate image 405 is converged on the image sensor 404 by the lens system 403 having a positive power to form an image.

  Here, the image sensor 404 is shifted in a direction approaching the document surface 401 in the X direction with respect to the optical axis 420 of the lens system 403 having positive power. Accordingly, the position at which the light beam strikes the reflecting surface 402 having a positive power shifts in a direction away from the document surface 401 in the X direction with respect to the optical axis 420 of the lens system 403. As a result, it becomes easier to separate a light beam incident on the reflective surface 402 having a positive power from a light beam emitted from the reflective surface 402 having a positive power. Furthermore, since it becomes possible to separate the light beam incident on the reflective surface 402 having positive power from the light beam emitted from the reflective surface 402 having positive power, the light beam emitted from the reflective surface 402 having positive power. In addition, the interference of the plane mirror 408 closest to the reflecting surface 402 having a positive power is less likely to occur, and the configuration of the imaging optical system becomes easier.

  In addition, when the intermediate image 405 is formed in the vicinity of the entrance pupil 106 of the light beam incident on the reflecting surface 402 having positive power in the direction perpendicular to the optical axis 420 of the lens system 403, the reflecting surface 402 having positive power. The light beam incident on becomes thin near the intermediate image 405. For this reason, interference of the plane mirror 408 closest to the reflecting surface 402 having a positive power, which is disposed in the vicinity of the entrance pupil 406, with respect to the light beam is more easily avoided, and the light beam is reflected on the reflecting surface 402 having the positive power. It is possible to reduce the shift of the position where the hit.

  Further, as described above, since the wide-angle imaging optical system is provided by forming the intermediate image 406, the distance between the object images of the imaging optical system is reduced. It becomes possible to shorten the optical path to the reflecting surface 402 which has. Therefore, when the size of the housing 430 of the image reading apparatus 400 is constant, the number of times of folding the optical path by the flat mirrors 408, 409, and 410 can be reduced. Accordingly, the number of plane mirrors 408, 409, and 410 installed in the image reading apparatus 400 can be reduced, leading to cost reduction of the image reading apparatus 400. Similarly, since it becomes possible to reduce the optical path length of the imaging optical system included in the image reading apparatus 400, the size of the housing 430 of the image reading apparatus 400, particularly the image reading apparatus 400 in the X direction in FIG. The height of the apparatus can be reduced, and the downsizing of the apparatus can be achieved.

  FIG. 5 is a diagram illustrating another example of an image reading apparatus according to an embodiment of the present invention.

  Here, the coordinate system in FIG. 5 is the same as the coordinate system in FIG. Further, in the image reading apparatus 500 shown in FIG. 5, the original surface 501, the reflecting surface 502 having positive power, the positive power lens system 503 and its optical axis 520, the image sensor 504, the contact glass 507, the plane mirrors 508 and 509, 510 and 511 and illumination means 515 are the same as those in the image reading apparatus 400 shown in FIG. In the image reading apparatus 500 shown in FIG. 5, the folding manner of the light beam emitted from the document surface 501 is different from the folding manner of the light beam in FIG. 4. More specifically, as shown in FIG. 5, the arrangement of the reflecting surface 502 having positive power and the imaging element 504 with respect to the optical axis 520 of the lens system 503 having positive power is opposite to the arrangement shown in FIG. In the image reading apparatus 500 shown in FIG. 5, a flat mirror 511 that folds the optical path of the imaging optical system is disposed at a position away from the document surface in the X direction with respect to the reflective surface 502 having positive power. An optical path from the document surface 501 to the reflective surface 502 having a positive power is formed in a space between the reflective surface 502 having a positive power and the lens system 503 having a positive power. In this case, the space between the reflecting surface 502 having positive power and the lens system 503 having positive power can be used effectively, and the overall height of the image reading apparatus 500 shown in FIG. It becomes possible to reduce.

  The number of plane mirrors that fold the optical path of the imaging optical system is three in the image reading apparatus 400 shown in FIG. 4 and four in the image reading apparatus 500 shown in FIG. The number of plane mirrors included in the imaging optical system in the image reading apparatus according to one embodiment is not limited. Further, the direction of folding the optical path of the imaging optical system by the plane mirror is not limited.

  In the image reading apparatus 400 shown in FIG. 4 and the image reading apparatus 500 shown in FIG. 5, when reading the image of the original 401 or 501, the entire housing 430 of the image reading apparatus 400 as shown in FIG. The entire housing of the image reading apparatus 500 as shown in FIG. 5 runs in the Z direction while maintaining its height relative to the document surface 401 or 501. At this time, the entire casing 430 of the image reading apparatus 400 or the entire casing of the image reading apparatus 500 as shown in FIG. 5 scans the image of the original surface 401 or 501, while the image is captured by the image sensor 404. Or read by 504 to form two-dimensional image information. Alternatively, two-dimensional image information can also be obtained by moving the document itself in the Z direction by using a paper feeder or the like.

  FIG. 6 is a diagram illustrating another example of an image reading apparatus according to an embodiment of the present invention.

  Here, the coordinate system in FIG. 6 is the same as the coordinate system in FIGS. 4 and 5. In addition, the document surface 601 in the image reading apparatus 600 shown in FIG. 6, the reflecting surface 602 having positive power, the lens system 603 having positive power, the image sensor 604, the contact glass 607, the plane mirrors 608, 609, 610, and 611. The illumination means 615 is the same as that in the image reading apparatus 400 shown in FIG. 4 and the image reading apparatus 500 shown in FIG.

  Further, in the image reading device 600 shown in FIG. 6, the image reading device 600 shown in FIG. 6 includes a first traveling body 641 including a flat mirror 611 that folds the optical path of the illumination unit 615 and the imaging optical system, and a flat surface. A second traveling body 642 including a mirror 609 and a plane mirror 610 is included. Here, the plane mirror 609 and the plane mirror 610 are attached to the second traveling body 642 such that their reflecting surfaces are orthogonal to each other. Further, the plane mirror 611 attached to the first traveling body 641 transmits the reflected light from the document surface 601 toward the plane mirror 610 attached to the second traveling body 642 (toward the −Z direction). They are arranged so as to be reflected parallel to the document surface 601 and parallel to the document surface 601 by the flat mirror 610 and the flat mirror 609 toward the flat mirror 108 (toward the + Z direction). In the image reading apparatus 600, the entire housing of the image reading apparatus 600 does not move, the first traveling body 641 travels in the Z direction parallel to the document surface 601, and the second traveling body 642 The document travels parallel to the document surface 601 at half the speed of the traveling body 641. At this time, the distance from the document surface 601 to the image sensor 604 is always kept constant, and the two-dimensional movement on the document surface 601 is caused by such travel of the first traveling body 641 and the second traveling body 642. Image information can be obtained.

[Example 5 (Numerical Example 1)]
Next, one design example of the imaging optical system in the image reading apparatus according to one embodiment of the present invention will be described below as Numerical Example 1.

  Table 1 shows the surface number, the radius of curvature, the surface interval, the refractive index, and the Abbe number of the optical elements constituting the imaging optical system of Numerical Example 1.

In addition, the refractive index shown in Table 1 is a value in d line (587.56 nm).

  In Table 1, the reflecting surface is indicated by a circle. The reflecting surfaces in the imaging optical system of Numerical Example 1 are the third surface and the fourth surface. The number of plane mirrors used in the imaging optical system of Numerical Example 1 to fold the optical path of the imaging optical system is only one, and the third surface is a plane mirror that folds the optical path of the imaging optical system. .

  The fourth surface is a reflecting surface having a positive power, and here is an anamorphic free-form surface.

The shape of the anamorphic free-form surface of the fourth surface in the imaging optical element of Numerical Example 1 is given by the formula:
Z (x, y) = c · r 2 / [1 + √ {1− (1 + k) c 2 r 2 }] + X4Y0 · x 4 + X2Y2 · x 2 y 2 + X0Y4 · y 4 + X5Y0 · x 5 + X3Y2 · x 3 y 2 + X1Y4 · x 1 y 4 + X6Y0 · x 6 + X4Y2 · x 4 y 2 + X2Y4 · x 2 y 4 + X0Y6 · y 6 +
It is represented by

In the above equation, when the direction of the normal of the anamorphic free-form surface at the center (surface vertex) of the anamorphic free-form surface is the z direction,
x is a coordinate in a first direction orthogonal to the z direction;
y is the coordinate in the second direction orthogonal to both the z direction and the first direction;
r is the height (r 2 = x 2 + y 2 ) in the direction perpendicular to the z direction,
Z (x, y) is a distance (sag amount) from the tangential plane of the center of the anamorphic aspheric surface to the anamorphic aspheric surface at the coordinates (x, y).
c is the curvature of the anamorphic aspheric surface at the center of the anamorphic aspheric surface (or the inverse of the radius of curvature);
k is the cone coefficient of the anamorphic aspheric surface at the center of the anamorphic aspheric surface,
X4Y0, X2Y2, X0Y4, X5Y0, X3Y2 ··· , respectively, term x 4, x 2 y 2 terms, term of y 4, the term x 5, with the coefficient of the term ... of x 3 y 2 is there.

  Table 2 shows data of an anamorphic free-form surface of the fourth surface in the imaging optical system of Numerical Example 1.

In Table 1, the eccentricity is indicated by ◯. In the imaging optical system of Numerical Example 1, the third surface and the fourth surface are decentered.

  Table 3 shows data of the decentering amounts of the third surface and the fourth surface in the imaging optical system of Numerical Example 1.

FIG. 7 is a diagram showing the configuration of the imaging optical system of Numerical Example 1 in the image reading apparatus according to one embodiment of the present invention. More specifically, FIG. 7 is a cross-sectional view of the imaging optical system of Numerical Example 1 in the XZ plane shown in FIG. As shown in FIG. 7, the data of the surface after the third surface given in Table 1 is in the XZ plane centering on the Y direction shown in FIG. It is described in a new X'Z 'coordinate system obtained by rotating it by .01 °. Further, the eccentricity of the fourth surface is an eccentricity within the local coordinates acting only on the fourth surface, and the coordinate system of the surface after the fourth surface is not affected by the eccentricity of the fourth surface.

  FIG. 8 is an enlarged view of a reflecting surface having a positive power and a lens system having a positive power in the imaging optical system of Numerical Example 1. FIG. FIG. 8A is a sectional view of a reflecting surface having a positive power and a lens system having a positive power included in the imaging optical system of Numerical Example 1 in the YZ ′ plane, and FIG. 2 is a cross-sectional view of a reflecting surface having a positive power and a lens system having a positive power included in the imaging optical system of Numerical Example 1 in the X′Z ′ plane. FIG.

  The imaging optical system of Numerical Example 1 is for an image reading apparatus having a reading density of 600 dpi, which forms an image of a document surface of an A3 size document by reducing it on a one-dimensional image sensor having a pixel pitch of 4.7 μm. The reduction magnification m of the imaging optical system of Numerical Example 1 is 0.11102. The brightness of the imaging optical system of Numerical Example 1 is Fno = 5.0, which is a sufficiently bright imaging optical system as a reading optical system for an image reading apparatus. Further, the half angle of view of the imaging optical system of Numerical Example 1 is 46.8 °, and the imaging optical system of Numerical Example 1 using a reflecting surface and an intermediate image having a positive power is a wide-angle optical system. It is a system. Although the imaging optical system of Numerical Example 1 is a wide-angle optical system, the object-to-image distance from the object to the image for the imaging optical system of Numerical Example 1 is 265.8 mm. In other words, the distance between the object images of the reading optical system of the conventional image reading apparatus is very short. Further, the lenses included in the imaging optical system of Numerical Example 1 (which constitutes a lens system having a positive power) are all spherical lenses, and the number of lenses included in the imaging optical system of Numerical Example 1 Although the number of lenses is five, the number of lenses is smaller than the number of lenses of the reading optical system composed of only lenses, for example. The effective area on the reflecting surface having positive power is rectangular in consideration of the pixel arrangement of the one-dimensional image sensor. More specifically, the length in the longitudinal direction of the effective region on the reflecting surface having a positive power corresponding to the direction of the pixel array of the one-dimensional image sensor is 50 mm. The length in the short direction of the (maximum) effective area on the reflecting surface having a positive power corresponding to the direction perpendicular to the direction (and the optical axis of the lens system having a positive power) is 5 mm. The ratio of the length in the short side direction of the effective area to the length in the long side direction is one tenth.

  FIG. 9 is a diagram illustrating the resolution performance of the imaging optical system of Numerical Example 1. The vertical axis of the graph shown in FIG. 9 shows the value of MTF (Modulation Transfer Function) of the synthesis of RGB three wavelengths (R: 612 nm, G: 546 nm, and B: 448 nm), and the horizontal axis of the graph shown in FIG. Indicates the defocus value in the Z-axis direction with respect to the image plane of the imaging optical system of Numerical Example 1. In the graph shown in FIG. 9, the light beams emitted from the points of height 0.0Y, 0.4Y, 0.7Y, 0.9Y, and 1.0Y on the object reach the image plane in order from the top. The resolution performance of the imaging optical system at a position where the image is received is shown, where Y is the distance (= 152.4 mm) from the center of the object to the point of the maximum angle of view in the object. Also, the solid line in the graph shown in FIG. 9 indicates the MTF value in the Y direction shown in FIGS. 7 and 8, and the dotted line in the graph shown in FIG. 9 indicates the MTF in the X ′ direction shown in FIGS. The value of is shown. The MTF value in the graph shown in FIG. 9 indicates that the imaging optical system of Numerical Example 1 has good resolution performance at any angle of view, which is sufficient as a reading optical system in the image reading apparatus. This shows a good reading performance.

  FIG. 10 is a diagram illustrating distortion aberration of the imaging optical system according to Numerical Example 1. The horizontal axis of the graph shown in FIG. 10 shows the distortion aberration value of the imaging optical system of Numerical Example 1 for light having a wavelength of 546 nm, and the vertical axis of the graph shown in FIG. 10 shows the image height on the image plane. As shown in FIG. 10, the distortion aberration of the image forming optical system of Numerical Example 1 is corrected well, and is sufficiently reduced as a reading optical system in the image reading apparatus.

[Example 6 (Numerical Example 2)]
Next, another design example of the imaging optical system in the image reading apparatus according to the embodiment of the present invention will be described below as Numerical Example 2.

  Table 4 shows the surface number, the radius of curvature, the surface interval, the refractive index, and the Abbe number of the optical elements constituting the imaging optical system of Numerical Example 2.

The refractive index shown in Table 4 is a value at d line (587.56 nm).

  In Table 4, the reflective surface is indicated by a circle. The reflecting surfaces in the imaging optical system of Numerical Example 2 are the third surface and the fourth surface. The number of plane mirrors used in the imaging optical system of Numerical Example 2 to fold the optical path of the imaging optical system is only one, and the third surface is a plane mirror that folds the optical path of the imaging optical system. .

  The fourth surface is a reflective surface having a positive power, and here is an anamorphic free-form surface represented by the formula described in Numerical Example 1.

  Table 5 shows data of an anamorphic free-form surface of the fourth surface in the imaging optical system of Numerical Example 2.

In Table 5, the eccentricity is indicated by ◯. Also in the imaging optical system of Numerical Example 2, as in the imaging optical system of Numerical Example 1, the third surface and the fourth surface are decentered.

  Table 6 shows data of the decentering amounts of the third surface and the fourth surface in the imaging optical system of Numerical Example 2.

FIG. 11 is a diagram showing the configuration of the imaging optical system of Numerical Example 2 in the image reading apparatus according to one embodiment of the present invention. More specifically, FIG. 11 is a cross-sectional view of the imaging optical system of Numerical Example 2 in the XZ plane shown in FIG. As shown in FIG. 11, the data of the surface after the third surface given in Table 4 is the amount of eccentricity −16 of the third surface shown in Table 6 in the XZ plane around the Y direction shown in FIG. 11. It is described in a new X′Z ′ coordinate system obtained by rotating it by 0.03 °. Further, the eccentricity of the fourth surface is an eccentricity within the local coordinates acting only on the fourth surface, and the coordinate system of the surface after the fourth surface is not affected by the eccentricity of the fourth surface.

  Similar to the imaging optical system of Numerical Example 1, the imaging optical system of Numerical Example 2 reduces the document surface of an A3-size document to a one-dimensional image sensor with a pixel pitch of 4.7 μm. This is a reading optical system for an image reading apparatus that forms an image and has a reading density of 600 dpi, and the reduction magnification m of the imaging optical system of Numerical Example 2 is 0.11102. Similarly to the imaging optical system of Numerical Example 1, the brightness of the imaging optical system of Numerical Example 2 is Fno = 5.0, and the imaging optical system is sufficiently bright as a reading optical system for an image reading apparatus. It is a system. Furthermore, the half angle of view of the imaging optical system of Numerical Example 2 is 47.6 °, and the imaging optical system of Numerical Example 2 using a reflecting surface and an intermediate image having a positive power is a wide-angle optical system. It is a system. Although the imaging optical system of Numerical Example 2 is a wide-angle optical system, the object-to-image distance from the object to the image in the imaging optical system of Numerical Example 2 is 263.0 mm. In other words, the distance between the object images of the reading optical system of the conventional image reading apparatus is very short. Further, the lenses included in the imaging optical system of Numerical Example 2 (which constitutes a lens system having a positive power) are all spherical lenses, and the number of lenses included in the imaging optical system of Numerical Example 2 The number of lenses is, for example, smaller than the number of lenses of the reading optical system composed of only lenses, and the lenses included in the imaging optical system of Numerical Example 1 It is one less than the number of sheets. The effective area on the reflecting surface having positive power is rectangular in consideration of the pixel arrangement of the one-dimensional image sensor. More specifically, the length in the longitudinal direction of the effective region on the reflecting surface having a positive power corresponding to the direction of the pixel array of the one-dimensional image sensor is 50 mm. The length in the short direction of the (maximum) effective area on the reflecting surface having a positive power corresponding to the direction perpendicular to the direction (and the optical axis of the lens system having a positive power) is 5 mm. The ratio of the length in the short side direction of the effective area to the length in the long side direction is one tenth.

  FIG. 12 is a diagram illustrating the resolution performance of the imaging optical system according to Numerical Example 2. The vertical axis of the graph shown in FIG. 12 indicates the value of MTF (Modulation Transfer Function) for the synthesis of RGB three wavelengths (R: 612 nm, G: 546 nm, and B: 448 nm), and the horizontal axis of the graph shown in FIG. Indicates the defocus value in the Z-axis direction with respect to the image plane of the imaging optical system of Numerical Example 2. In the graph shown in FIG. 12, in order from the top, rays emitted from points of height 0.0Y, 0.4Y, 0.7Y, 0.9Y, and 1.0Y on the object reach the image plane, respectively. The resolution performance of the imaging optical system at a position where the image is received is shown, where Y is the distance (= 152.4 mm) from the center of the object to the point of the maximum angle of view in the object. Also, the solid line in the graph shown in FIG. 12 indicates the MTF value in the Y direction shown in FIG. 11, and the dotted line in the graph shown in FIG. 12 indicates the MTF value in the X ′ direction shown in FIG. . The MTF value in the graph shown in FIG. 12 indicates that the imaging optical system of Numerical Example 2 has good resolution performance at any angle of view, which is sufficient as a reading optical system in the image reading apparatus. This shows a good reading performance.

  FIG. 13 is a diagram illustrating distortion aberration of the imaging optical system according to Numerical Example 2. The horizontal axis of the graph shown in FIG. 13 indicates the distortion aberration value of the imaging optical system of Numerical Example 2 with respect to light having a wavelength of 546 nm, and the vertical axis of the graph shown in FIG. 13 indicates the image height on the image plane. As shown in FIG. 13, the distortion aberration of the imaging optical system of Numerical Example 2 is corrected well, and is sufficiently reduced as the reading optical system in the image reading apparatus.

[Example 7]
FIG. 14 is a diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.

  The copier 700 is an image forming apparatus that forms an image by executing an electrophotographic process. The copier 700 includes an image scanner 800 that reads image information in an electrophotographic process and a printer 900 disposed below the image scanner 800. Here, the image scanner 800 is an image reading apparatus according to an embodiment of the present invention.

  First, the configuration and operation of the image scanner 800 will be described. The image reading unit of the image scanner 800 is provided with a transparent contact glass 807 that functions as a base for a document 801 such as a paper sheet and a plastic film, and a pressure plate 850 that can be opened and closed is disposed above the transparent contact glass 807. ing. The color of the inner surface of the pressure plate 350, that is, the color of the portion facing the back surface of the document 801 is white. Below the contact glass 807, a reading optical system included in the image reading apparatus according to one embodiment of the present invention is provided. The reading optical system includes an exposure lamp 815, flat mirrors 810, 809, and 805, a reflective surface 802 having a positive power, a lens system 803 having a positive power, and an image sensor 804. The reading optical system is mechanically driven in the left-right direction of the document surface. Light emitted from the exposure lamp 815 is reflected by the surface inside the document 801 or the pressure plate 850, and the reflected light has plane mirrors 810, 809, 805, a reflecting surface 802 having positive power, and positive power. The light enters the image sensor 804 through the lens system 803. Here, since an intermediate image is formed between the reflecting surface 802 having positive power and the lens system 803 having positive power, the reading optical system is a wide-angle optical system. The object-to-image distance for the system is reduced. As a result, the height of the image scanner 800 can be reduced.

  Next, the configuration and operation of the printer 900 will be described. A printer 900 that performs image formation and transfer operations includes a writing unit 901, a photoconductor 902, a revolver unit 903, a transfer unit 904, a paper feed unit 905, a transfer paper transport path 906, and a fixing unit 907. Around the photosensitive member 902, a static elimination lamp 908, a charging charger 909, a revolver unit 903, a transfer unit 904, and a drum cleaning unit 910 are provided along the rotation direction of the photosensitive member 902. The revolver unit 903 includes developing devices for each color of black (Bk), cyan (C), magenta (M), and yellow (Y). The transfer unit 904 is stretched and rotated by a plurality of rollers, and an intermediate transfer belt 912 having a belt mark 911, a primary transfer roller 913, an alignment sensor 914 for reading the belt mark 911, a secondary transfer roller 915, and a belt cleaning. Part 916.

  First, the image information read by the image scanner 800 is subjected to predetermined image processing, and then based on the processed image information, a writing unit 901 including a laser light source or the like is used to charge the charger 909. As a result, an electrostatic latent image is formed on the photosensitive member 902 electrostatically charged. Next, the electrostatic latent image formed on the photoconductor 902 is developed with a developer containing toner prepared in each color developer included in the revolver unit 903, and a toner image as a copy image is developed on the photoconductor 902. Form. The toner image formed on the photoconductor 902 is primarily transferred to the intermediate transfer belt 912. Here, the image formation on the photosensitive member 902 and the primary transfer of the toner image on the intermediate transfer belt 912 are repeated based on detection of the belt mark 911 for each color, and a predetermined color image is superimposed on the intermediate transfer belt 912. Next, the toner image is secondarily transferred onto the sequentially fed transfer paper in accordance with the leading edge of the toner image transferred to the intermediate transfer belt 912. Next, the toner image transferred onto the transfer paper is fixed by using the fixing unit 907, and the transfer paper on which the toner image is fixed is discharged from the printer 900. Finally, the toner remaining on the intermediate transfer belt 912 is collected by using the cleaning unit 916.

  Here, since the image scanner 800 is an image reading apparatus according to an embodiment of the present invention, the copier 700 is a small image forming apparatus, and forms a good image, that is, outputs a high-quality image. Can be realized.

  Although the embodiments and examples of the present invention have been specifically described above, the present invention is not limited to these embodiments and examples, and these embodiments and examples of the present invention are not limited thereto. Can be changed or modified without departing from the spirit and scope of the present invention.

[Appendix]

Appendix (1):
In an image reading apparatus that reads image information, including an imaging optical system that forms an image into an image and an image sensor that images at least a part of the image formed by the imaging optical system.
The imaging optical system includes: a first optical system that forms the image on an intermediate image; and a second optical system that forms the intermediate image on the formed image. Reader.

Appendix (2):
The first optical system includes a reflecting surface having a positive power,
The second optical system includes a lens system having an optical axis and a positive power.
The image reading apparatus according to appendix (1), characterized in that:

Appendix (3):
The imaging optical system further includes at least one reflecting surface that folds an optical path from the image to the imaged image and does not have power, according to appendix (1) or (2), The image reading apparatus described.

Appendix (4):
The at least one reflecting surface that folds the optical path from the image to the image formed and has no power folds the optical path from the image to the reflecting surface having the positive power and has power. The image reading device according to (3), further including at least one reflecting surface.

Appendix (5):
Of the at least one reflecting surface that folds the optical path from the image to the reflecting surface having the positive power and does not have the power, the reflecting surface that does not have the power closest to the reflecting surface having the positive power is The additional information (4) is characterized in that the lens system is arranged at the position of the intermediate image or at a position between the intermediate image and the lens system having the positive power with respect to the direction of the optical axis of the lens system. Image reading apparatus.

Appendix (6):
Of the at least one reflecting surface that folds the optical path from the image to the reflecting surface having the positive power and does not have the power, the reflecting surface that does not have the power closest to the reflecting surface having the positive power is The image reading apparatus according to (4) or (5), wherein the image reading apparatus is disposed at an entrance pupil position of any ray incident on the reflection surface having the positive power from the image.

Appendix (7):
The image reading apparatus according to any one of appendices (2) to (6), wherein the number of lenses having power constituting the lens system is 3 or more and 6 or less.

Appendix (8):
The image reading apparatus according to any one of appendices (2) to (7), wherein an image plane of the intermediate image is curved so as to approach the lens system as the distance from the optical axis of the lens system increases.

Appendix (9):
The image reading apparatus according to any one of appendices (2) to (8), wherein the reflecting surface having positive power has an anamorphic aspherical shape.

Appendix (10):
The image sensor has pixels arranged in at least a first direction and is shifted in a direction perpendicular to both the first direction and the direction of the optical axis of the lens system with respect to the optical axis of the lens system. The image reading apparatus according to any one of appendices (2) to (9), wherein

Appendix (11):
The imaging device includes pixels arranged in at least a first direction, and a reflective surface having the positive power in a direction perpendicular to both the first direction and the direction of the optical axis of the lens system. The image reading apparatus according to any one of appendices (2) to (10), wherein a length is equal to or less than half of a length of the reflecting surface having the positive power in the first direction. .

Appendix (12):
The image sensor has pixels arranged in at least a first direction, and folds an optical path from the image to the imaged image in the first direction and has no power. The length of one reflecting surface is smaller than the length of the reflecting surface having the positive power in the first direction, and the image reading device according to any one of appendices (3) to (11), .

Appendix (13):
In an image reading method for reading image information,
An image reading method comprising reading image information using the image reading apparatus according to any one of appendices (1) to (12).

Appendix (14):
In an image forming apparatus for forming an image on an image carrier,
An image comprising the image reading apparatus according to any one of appendices (1) to (12) and a device that forms an image on the image carrier using information of an image read by the image reading apparatus. Forming equipment.

Appendix (15):
In an image forming method for forming an image on an image carrier,
An image forming method comprising: forming an image on the image carrier using the image forming apparatus according to appendix (14).

  The embodiments of the present invention are considered to be applicable to an image reading apparatus, an image reading method, an image forming apparatus, and an image forming method.

There is a possibility that at least one aspect of the present invention can be used in at least one of an image reading apparatus and an image forming apparatus.

FIG. 1 is a diagram illustrating an example of an imaging optical system in an image reading apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating another example of the imaging optical system in the image reading apparatus according to one embodiment of the present invention. FIG. 3 is a diagram illustrating another example of the imaging optical system in the image reading apparatus according to one embodiment of the present invention. FIG. 4 is a diagram illustrating an example of an image reading apparatus according to an embodiment of the present invention. FIG. 5 is a diagram illustrating another example of an image reading apparatus according to an embodiment of the present invention. FIG. 6 is a diagram illustrating another example of an image reading apparatus according to an embodiment of the present invention. FIG. 7 is a diagram showing the configuration of the imaging optical system of Numerical Example 1 in the image reading apparatus according to one embodiment of the present invention. FIG. 8 is an enlarged view of a reflecting surface having a positive power and a lens system having a positive power in the imaging optical system of Numerical Example 1. FIG. FIG. 9 is a diagram illustrating the resolution performance of the imaging optical system of Numerical Example 1. FIG. 10 is a diagram illustrating distortion aberration of the imaging optical system according to Numerical Example 1. FIG. 11 is a diagram showing the configuration of the imaging optical system of Numerical Example 2 in the image reading apparatus according to one embodiment of the present invention. FIG. 12 is a diagram illustrating the resolution performance of the imaging optical system according to Numerical Example 2. FIG. 13 is a diagram illustrating distortion aberration of the imaging optical system according to Numerical Example 2. FIG. 14 is a diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention.

100, 100 ′, 200, 300 Imaging optical system 101, 101 ′, 201, 401, 501, 601 Document surface 102, 102 ′, 202, 302, 402, 502, 602, 802 Reflective surface 103 having positive power , 103 ′, 203, 303, 403, 503, 603, 803 Lens system having positive power 104, 104 ′, 204, 304, 404, 504, 604, 804 Image sensor 105, 205, 305, 405 Intermediate image 206 , 406 Entrance pupil 207, 407, 507, 607, 807 Contact glass 208, 308, 408, 409, 410, 508, 509, 510, 511, 608, 609, 610, 611, 805, 809, 810 Planar mirror 320, 420 Optical axis 400, 500, 600 Image reading device 415, 515 615 Illuminating means 430 Case 641 First traveling body 642 Second traveling body 700 Copying machine 800 Image scanner 801 Document 850 Pressure plate 900 Printer 901 Writing unit 902 Photoreceptor 903 Revolver unit 904 Transfer unit 905 Paper feed unit 906 Transfer paper transport Path 907 Fixing unit 908 Static elimination lamp 909 Charging charger 910 Drum cleaning unit 911 Belt mark 912 Intermediate transfer belt 913 Primary transfer roller 914 Position sensor 915 Secondary transfer roller 916 Belt cleaning unit

Claims (10)

  1. In an image reading apparatus that reads image information,
    The image reading apparatus includes an imaging optical system that forms an image into an image, and an imaging element that captures at least a part of the image formed by the imaging optical system.
    The imaging optical system includes a first optical system that forms the image on an intermediate image and a second optical system that forms the intermediate image on the formed image;
    The first optical system includes a reflecting surface having a positive power,
    The second optical system includes a lens system having an optical axis and positive power,
    The imaging optical system further includes at least one reflecting surface that folds an optical path from the image to the reflecting surface having the positive power and has no power, and
    Of the at least one reflecting surface that folds the optical path from the image to the reflecting surface having the positive power and does not have power, the reflecting surface that has no power closest to the reflecting surface having the positive power is: Intersects the optical axis of the lens system
    An image reading apparatus.
  2. The image reading apparatus according to claim 1,
    The reflecting surface that has no power closest to the reflecting surface having the positive power is located at the position of the intermediate image or of the intermediate image and the lens system having the positive power with respect to the direction of the optical axis of the lens system. Is located between
    An image reading apparatus.
  3. The image reading apparatus according to claim 1 or 2,
    The reflection surface that does not have the power closest to the reflection surface having the positive power is disposed at the entrance pupil position of any light ray that enters the reflection surface having the positive power from the image.
    An image reading apparatus.
  4. In the image reading device according to any one of claims 1 to 3,
    The number of lenses having power constituting the lens system is 3 or more and 6 or less.
    An image reading apparatus.
  5. The image reading apparatus according to any one of claims 1 to 4,
    The image plane of the intermediate image is curved so as to approach the lens system as the distance from the optical axis of the lens system increases.
    An image reading apparatus.
  6. The image reading apparatus according to any one of claims 1 to 5,
    The reflective surface having positive power has an anamorphic aspherical shape.
    An image reading apparatus.
  7. The image reading apparatus according to any one of claims 1 to 6,
    The image sensor has pixels arranged in at least a first direction and is shifted in a direction perpendicular to both the first direction and the direction of the optical axis of the lens system with respect to the optical axis of the lens system. It was made
    An image reading apparatus.
  8. The image reading apparatus according to any one of claims 1 to 6,
    The image sensor has pixels arranged in at least a first direction,
    The length of the reflecting surface having the positive power in the direction perpendicular to both the first direction and the direction of the optical axis of the lens system is the length of the reflecting surface having the positive power in the first direction. Less than half
    An image reading apparatus.
  9. The image reading apparatus according to any one of claims 1 to 6,
    The image sensor has pixels arranged in at least a first direction,
    The length of the at least one reflecting surface that folds the optical path from the image to the reflecting surface having the positive power and does not have power in the first direction is the positive power in the first direction. Less than the length of the reflective surface
    An image reading apparatus.
  10. In an image forming apparatus for forming an image on an image carrier,
    The image forming apparatus includes an image reading apparatus according to any one of claims 1 to 9 and a device that forms an image on the image carrier using information of an image read by the image reading apparatus.
    An image forming apparatus.
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